S.Art2 (or Super Articulation 2) and AEM (or Articulation Element Modeling) are trademarked Yamaha tone generator systems found in high end Digital Pianos, Clavinovas and Tyros series keyboards.

If you are familiar with these terms and what they are capable of then you know they provide ways to manipulate and manage audio samples during realtime performance. On the products containing these systems, you perform the Factory sound via control switches, aftertouch, pedals, etc.

If you are at all familiar with Montage, while the same trademarked names are not used, you can see that the tech behind what's on offer is from the same lab. In Montage, being a synthesizer, however, it is User programmable to a degree not available in the trademarked presentations.

The Tyros 5 for example, is often called a synthesizer - and in the broad sense, it is. But it is not the 'roll your sleeves up and create a sound' type of synthesizer that the Montage is. So this difference is huge. The Montage is programmable.

Super Articulation 2 and Articulation Element Modeling are found in upscale Yamaha products at this point. The Tyros 5(61-key) is the starting point.
In US Dollars a Tyros 5 61-Key retails for $2000 more than a Montage 8, and is $3000 more retail than 61-Key Montage. Just for some perspective.

The "XA CONTROL" (Expanded Articulation Control) feature found in MOXF, Motif XS/XF and now Montage series allows for some of the dynamic realtime change found in the SA2 and AEM engines, but in a user programmable form. Montage has also broken the architecture open so that, much like in the AEM engine, you can have (add) additional Elements brought in on-demand as you perform.

A programmable implementation of SA2 and AEM is available in Montage, they are not called by their official names because they are not identical... but if you are paying attention you can see they are from the same lab /cut from the same mold.

Using multiple Parts is how Montage is able to construct sounds with the kind of detail you find in SA2 and AEM sounds. These specialty sounds use the synth architecture to construct nuance via Element control. The Motion Control engine and the AWM2 system of Element management is what's new about Montage. Instead of recalling a brass section sound that is limited in horn section articulations, you can have an array of horn section moves at your beck and call.

See Tony Escueta's video tutorial on Layering sounds and controlling them in real time.
Mastering Montage: Splits-Layers-Scenes and Articulations

The short answer appears to be that Montage does not offer full SA2 because it "costs" (retails for) less and is a differentiating feature for Tyros - so buy a Tyros if you need that feature.

But you can almost get there by using something that is different - XA plus MC.

I say "almost" because full SA2 still has control that cannot be done on the Montage despite it's relatively more "open" architecture allowing deeper editing.

Legato based on interval is an example. SA2 allows for limiting legato only within a given interval and interpreting as not legato (even if played legato) if outside of the programmed interval.

There are other differences.

In my opinion, I think a user coming at Yamaha with some fairly technical terms like SA2 and AEM would know what they're asking about - and it is true that Montage does not offer these.

Therefore, I do think this part of your answer is the best and most applicable response to the original question:

Super Articulation 2 and Articulation Element Modeling are found in upscale Yamaha products at this point. In US Dollars a Tyros 5 61-Key retails for $2000 more than a Montage 8, and is $3000 more retail than 61-Key Montage. Just for some perspective.

As far as being cut from the same mold - absolutely true. The underlying hardware to accomplish SA2 and AEM are there as the "chipset" is shared between products. But to say that XA + MC is somehow SA2+AEM is not accurate even when you normalize for the differences in programming access. It would seem the presentation is that SA2+AEM is somehow a subset of XA + MC, but it's more the other way around. Yes, XA + MC may add the programming feature - but takes away lots of other features which are part of the SA2+AEM "bundle". Ignoring editing, XA+MC is a subset of SA2+AEM.

Once you can start editing - it doesn't just "open the door" to the SA2+AEM features. It just allows more tweaking of what is a smaller pool than the larger pool of SA2+AEM features which does not have as many chances for tweaking.

I personally think it's fine to have product differentiation and to draw clear lines that say one product "IS/IS NOT" XYZ and another product "IS/IS NOT" LMNOP - because it's important to have a clear choice in models and to have products which are affordable to users at different price bands. As the lines get blurred - the rationale for carrying multiple models gets blurred - then either Tyros loses something or Montage costs even more than it does already. Of course I'd love to have the kitchen sink in my Montage - but have to respect the definition of the product and either respond, individually, using market controls (purchase or not purchase). Compelling/asking for features is another choice - you've done that - perfectly valid.

BM - I'm mostly OK with the response and appreciate the candor regarding why SA2 may not be part of Montage. Even though you do correctly say Montage's articulation is different than SA2+AEM (true), flexible/programmable (true), and highly related to SA+AEM due to common "mold"/parts (true) - it's where you nearly say it's the same thing just relabeled that I think the response gets off the tracks a bit. I do understand you technically didn't do this - but not listing the limitations and (negative) differences leaves the more casual or less informed reader easily drawing a false equivalency. You did list one of the differences which is in favor of Montage - the editing advantage to Montage. However, differences which are not in favor of Montage were left out - although there are a handful.

On the CP4 thread ...

Montage doesn't "do" any modeling-type work, in terms of the engine, except for FM-X. Otherwise, it's a ROMpler with fancy automation. Ignoring FM-X, Montage isn't trying to model analog synths, organs, pianos, string instruments, acoustic/wind instruments, etc. Instead, it's "just" trying to reproduce ("photo copy") instruments using sample playback and nuance manipulation. The modeling is left open for another product which Montage, with 8 channels of MIDI outputs controlled by the keybed, is up for the task. Instead of plug-in cards to achieve modeled analog, virtual/modeled instruments, enhanced piano, etc - you buy an external MIDI device. Maybe the external device has its own keybed, maybe it doesn't.

I get not agreeing with this - thinking the price-point may justify at least one other engine or some means of expanding (plug-in cards). But when compared vs. Motif XF - in terms of engines you get double (AWM2 - enhanced plus FM-X).

We traded sampling and a sequencer for FM-X and motion control. Depending on where you fall on the perception-of-utility spectrum, this may leave you at a deficit. But ignoring everything else (as is the general theme of how you open) - just on engines alone Montage doubles the previous offering.

Also, it's worth mentioning before I get push-back - that I'm ignoring effects and sticking to the main engines when I describe modeling. Of course the latest rotary speaker effect does some modeling of a Leslie-type speaker. The rotary speaker effect is far from a full-fledged engine such as AWM2, FM-X, AN*, VL*, etc... (from Yamaha), or other engines from the competition such as SGX*, EP*, CX*, MS*, AL*, STR*, etc.